getcustomvariable.js

<script type="text/javascript">

	document.addEventListener('om.Dtr.init', function(event) {

		/**

		 * API method for retrieving a custom variable. Must be accessed via the app object.

		 *

		 * @param string $key  The custom variable key to retrieve.

		 * @return string|bool The value of the custom variable key or false if not found.

		 */

		event.detail.Dtr.getCustomVariable('foo');

	});

</script>